feat: Add Docker utility library

- Add lib/docker.sh with container management functions
- Add cleanup_docker function for container cleanup
- Add run_container function for container execution
- Add exec_in_container function for command execution

💘 Generated with Crush

Assisted-by: GLM-4.6 via Crush <crush@charm.land>

lib/docker.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# Docker utility functions
+set -euo pipefail
+
+# Clean up Docker containers on exit
+cleanup_docker() {
+  local container_name="${1:-}"
+  if [ -n "$container_name" ] && docker ps -q --filter "name=^${container_name}$" | grep -q .; then
+    echo "Removing Docker container: $container_name"
+    docker rm -f "$container_name" || true
+  fi
+}
+
+# Run Docker container with automatic cleanup
+run_container() {
+  local image="${1:-}"
+  local name="${2:-}"
+  local cmd="${3:-}"
+
+  # Clean up existing container if it exists
+  cleanup_docker "$name"
+
+  # Run new container with explicit name
+  echo "Starting Docker container: $name"
+  docker run --name "$name" -it --rm "$image" $cmd
+}
+
+# Execute command in container
+exec_in_container() {
+  local container="${1:-}"
+  shift
+  docker exec -it "$container" "$@"
+}